This invention relates generality to cleaning devices. More specifically, the present invention relates to an improved cleaning head assembly for a vacuum cleaning apparatus of the wet, dry and wet/dry types.
Many prior devices for cleaning rugs, carpets and the like have consisted basically of a system for delivering cleaning solution (usually a hot aqueous detergent solution) to the rug or carpet, and a system for vacuuming the applied cleaning solution from the rug or carpet. Many such "vacuum cleaners" or carpet cleaning machines have been provided with a rotatable brush which is intended to contact and brush the surface to be cleaned, to loosen and agitate dirt, grit and debris so that it can be sucked up into a collection tank or bag by a vacuum motor. The brush is able to perform its intended purpose only to the extent the distal ends of the bristles of the brush are in contact with the surface being cleaned. Keeping the brush in contact is not a problem provided the surface being cleaned is absolutely uniform, smooth and level. However, in most cases, the surface is irregular or bumpy. When this irregular surface condition exists, the efficiency of the brush is diminished, since only some of the bristles can contact the surface being cleaned. One of the best devices for maintaining contact between the brush and the surfaces being cleaned where the surface is irregular is shown in U.S. Pat. No. 4,976,003, entitled CLEANING APPARATUS, and issued to one of the inventors herein.
A typical vacuum system for a carpet cleaning device generally comprises a vacuum chamber or nozzle disposed in a cleaning head assembly which is positioned over the rug, carpet or the like to "suck up" applied cleaning solution, dirt and other debris, and a vacuum pump in fluid communication with the cleaning head assembly to generate a partial vacuum therein. There are two variations of the basic system found in the marketplace. In one embodiment, the cleaning head, the solution delivery system, the vacuum system, and one or more solution tanks are integrated into a single wheeled housing which is pulled over the rug or carpet by the operator. In the other embodiment, the cleaning head is a separate unit from a wheeled housing containing the vacuum system, the solution delivery system and the solution tanks. Both embodiments have advantages and disadvantages. For example, the cleaning unit having a separate cleaning head is easier to manipulate over a rug or carpet surface, but because of the additional distance the fresh solution must be pumped to the cleaning head and the spent solution must be transferred back to the housing after the aspiration thereof from the rug or carpet, the power requirements for both the solution pump and the vacuum pump are substantially increased. Moreover, the connections for the tubings for the separate cleaning head present maintenance problems because they frequently leak solution.
The cleaning devices which are completely contained within a wheeled housing are most desirable from a manufacturing and maintenance point of view, but they are more difficult to move over a rug or carpet surface during the cleaning operation, especially where space is limited, for example in small offices or narrow hallways. As a result, their use was traditionally limited to professional or commercial rug and carpet cleaners. A significant advancement in the construction of such cleaning devices is shown in U.S. Pat. No. 5,189,757, entitled HEAD ASSEMBLY FOR A VACUUM CLEANING APPARATUS.
In spite of numerous improvements in the design of prior cleaning devices, optimal performance has not yet been realized, particularly where the surface to be cleaned is irregular or bumpy. In order to "suck up" applied cleaning solution, dirt and other debris, it is important to maintain an inlet of a vacuum head in close intimate contact with the floor surface. This is particularly difficult to accomplish with cleaning devices which are completely contained within a wheel housing.
Accordingly, there has been a need for a novel vacuum cleaning apparatus of the wet, dry and wet/dry types having a proven, durable construction, which can be easily maneuvered over a surface to be cleaned during the cleaning operation, and is constructed in a manner which ensures that inlet openings of the vacuum head are placed adjacent to the surface to be cleaned, even when the surface is irregular of bumpy. Such a novel vacuum cleaning apparatus may include heads which are permitted to follow the contour of the surface to be cleaned independently of a supporting housing. Further, there exists a need for a novel cleaning head assembly for use in a vacuum cleaning apparatus which permits the apparatus to be either pushed or pulled, and yet provide means for adequately sucking up debris loosened by the cleaning brush without reducing the vacuum drawn through the cleaning head. The present invention fulfills these needs and provides other related advantages.